Rename HNativeDebugInfo to HNop

We can generalize HNativeDebugInfo to be used as a Nop (i.e. no
instructions are generated), and give it the option of having an
environment to keep the current HNativeDebugInfo logic working.

Test: art/test/testrunner/testrunner.py --host --64 --optimizing -b
Change-Id: I06b3a36e8b124bcda858d2c9cd8ff0ab21caea36
8 files changed